TandEM problem. More...

#include <tandem.h>

Inheritance diagram for pagmo::problem::tandem:

Public Member Functions
	tandem (const int problemid=6, const double tof_=-1)
	Constructor. More...

base_ptr	clone () const
	Clone method.

std::string	pretty (const std::vector< double > &x) const
	Outputs a stream of the trajectory data. More...

std::string	get_name () const
	Get problem's name. More...

Public Member Functions inherited from pagmo::problem::base
	base (int, int=0, int=1, int=0, int=0, const double &=0)
	Constructor from global dimension, integer dimension, fitness dimension, global constraints dimension, inequality constraints dimension and constraints tolerance. More...

	base (int, int, int, int, int, const std::vector< double > &)
	Constructor from global dimension, integer dimension, fitness dimension, global constraints dimension, inequality constraints dimension and constraints tolerance. More...

	base (const double &, const double &, int, int=0, int=1, int=0, int=0, const double &=0)
	Constructor from values for lower and upper bounds, global dimension, integer dimension, fitness dimension, global constraints dimension, inequality constraints dimension and constraints tolerance. More...

	base (const decision_vector &, const decision_vector &, int=0, int=1, int=0, int=0, const double &=0)
	Constructor from upper/lower bounds, integer dimension, fitness dimension, global constraints dimension, inequality constraints dimension and constraints tolerance. More...

template<std::size_t N>
	base (const double(&v1)[N], const double(&v2)[N], int ni=0, int nf=1, int nc=0, int nic=0, const double &c_tol=0)
	Constructor from raw arrays, integer dimension, fitness dimension, global constraints dimension, inequality constraints dimension and constraints tolerance. More...

template<class Iterator1 , class Iterator2 >
	base (Iterator1 start1, Iterator1 end1, Iterator2 start2, Iterator2 end2, int ni=0, int nf=1, int nc=0, int nic=0, const double &c_tol=0)
	Constructor from iterators, integer dimension, fitness dimension, global constraints dimension, inequality constraints dimension and constraints tolerance. More...

virtual	~base ()
	Trivial destructor. More...

std::string	human_readable () const
	Return human readable representation of the problem. More...

virtual std::string	human_readable_extra () const
	Extra information in human readable format. More...

bool	operator== (const base &) const
	Equality operator. More...

bool	operator!= (const base &) const
	Inequality operator. More...

bool	is_compatible (const base &) const
	Compatibility operator. More...

bool	compare_x (const decision_vector &, const decision_vector &) const
	Compare decision vectors. More...

bool	verify_x (const decision_vector &) const
	Verify compatibility of decision vector x with problem. More...

bool	compare_fc (const fitness_vector &, const constraint_vector &, const fitness_vector &, const constraint_vector &) const
	Simultaneous fitness-constraint comparison. More...

virtual void	pre_evolution (population &) const
	Pre-evolution hook. More...

virtual void	post_evolution (population &) const
	Post-evolution hook. More...

const decision_vector &	get_lb () const
	Lower bounds getter. More...

const decision_vector &	get_ub () const
	Upper bounds getter. More...

void	set_bounds (const decision_vector &, const decision_vector &)
	Bounds setter from pagmo::decision_vector. More...

template<class Iterator1 , class Iterator2 >
void	set_bounds (Iterator1 start1, Iterator1 end1, Iterator2 start2, Iterator2 end2)
	Bounds setter from iterators. More...

template<std::size_t N>
void	set_bounds (const double(&v1)[N], const double(&v2)[N])
	Bounds setter from raw arrays. More...

void	set_bounds (const double &, const double &)
	Set bounds to specified values. More...

void	set_bounds (int, const double &, const double &)
	Set bounds to specified values. More...

void	set_lb (const decision_vector &)
	Set lower bounds from pagmo::decision_vector. More...

void	set_lb (int, const double &)
	Set specific lower bound to value. More...

void	set_lb (const double &)
	Set all lower bounds to value. More...

template<class Iterator >
void	set_lb (Iterator start, Iterator end)
	Lower bounds setter from iterators. More...

template<std::size_t N>
void	set_lb (const double(&v)[N])
	Lower bounds setter from raw array. More...

void	set_ub (const decision_vector &)
	Set upper bounds from pagmo::decision_vector. More...

void	set_ub (int, const double &)
	Set specific upper bound to value. More...

void	set_ub (const double &)
	Set all upper bounds to value. More...

template<class Iterator >
void	set_ub (Iterator start, Iterator end)
	Upper bounds setter from iterators. More...

template<std::size_t N>
void	set_ub (const double(&v)[N])
	Upper bounds setter from raw array. More...

unsigned int	get_fevals () const
	Return number of function evaluations. More...

unsigned int	get_cevals () const
	Return number of constraints function evaluations. More...

size_type	get_dimension () const
	Return global dimension. More...

size_type	get_i_dimension () const
	Return integer dimension. More...

f_size_type	get_f_dimension () const
	Return fitness dimension. More...

c_size_type	get_c_dimension () const
	Return global constraints dimension. More...

c_size_type	get_ic_dimension () const
	Return inequality constraints dimension. More...

const std::vector< double > &	get_c_tol () const
	Return constraints tolerance. More...

double	get_diameter () const
	Get the diameter of the problem. More...

constraint_vector	compute_constraints (const decision_vector &) const
	Compute constraints and return constraint vector. More...

void	compute_constraints (constraint_vector &, const decision_vector &) const
	Compute constraints and write them into contraint vector. More...

bool	compare_constraints (const constraint_vector &, const constraint_vector &) const
	Compare constraint vectors. More...

bool	test_constraint (const constraint_vector &, const c_size_type &) const
	Test i-th constraint of c (using tolerance information). More...

bool	feasibility_x (const decision_vector &) const
	Test feasibility of decision vector. More...

bool	feasibility_c (const constraint_vector &) const
	Test feasibility of constraint vector. More...

fitness_vector	objfun (const decision_vector &) const
	Return fitness of pagmo::decision_vector. More...

void	objfun (fitness_vector &, const decision_vector &) const
	Write fitness of pagmo::decision_vector into pagmo::fitness_vector. More...

bool	compare_fitness (const fitness_vector &, const fitness_vector &) const
	Compare fitness vectors. More...

void	reset_caches () const
	Reset internal caches. More...

const std::vector< constraint_vector > &	get_best_c (void) const
	Get the best known constraint vector. More...

const std::vector< decision_vector > &	get_best_x (void) const
	Get the best known decision vector. More...

const std::vector< fitness_vector > &	get_best_f (void) const
	Get the best known fitness vector. More...

void	set_best_x (const std::vector< decision_vector > &)
	Sets the best known decision vectors. More...

Protected Member Functions
void	objfun_impl (fitness_vector &, const decision_vector &) const
	Implementation of the objective function.

void	set_sparsity (int &, std::vector< int > &, std::vector< int > &) const
	Implementation of the sparsity structure. More...

Protected Member Functions inherited from pagmo::problem::base
virtual bool	equality_operator_extra (const base &) const
	Extra requirements for equality. More...

virtual bool	compare_fc_impl (const fitness_vector &, const constraint_vector &, const fitness_vector &, const constraint_vector &) const
	Implementation of simultaneous fitness-constraint comparison. More...

void	estimate_sparsity (const decision_vector &, int &lenG, std::vector< int > &iGfun, std::vector< int > &jGvar) const
	Heuristics to estimate the sparsity pattern of the problem. More...

void	estimate_sparsity (int &lenG, std::vector< int > &iGfun, std::vector< int > &jGvar) const
	Heuristics to estimate the sparsity pattern of the problem. More...

virtual void	compute_constraints_impl (constraint_vector &, const decision_vector &) const
	Implementation of constraint computation. More...

virtual bool	compare_constraints_impl (const constraint_vector &, const constraint_vector &) const
	Implementation of constraint vector comparison. More...

virtual bool	compare_fitness_impl (const fitness_vector &, const fitness_vector &) const
	Implementation of fitness vectors comparison. More...

Friends
class	boost::serialization::access

Additional Inherited Members
Public Types inherited from pagmo::problem::base
typedef decision_vector::size_type	size_type
	Problem's size type: the same as pagmo::decision_vector's size type.

typedef fitness_vector::size_type	f_size_type
	Fitness' size type: the same as pagmo::fitness_vector's size type.

typedef constraint_vector::size_type	c_size_type
	Constraints' size type: the same as pagmo::constraint_vector's size type.

Static Public Attributes inherited from pagmo::problem::base
static const std::size_t	cache_capacity = 5
	Capacity of the internal caches.

Detailed Description

TandEM problem.

Encedalus orbiting around Saturn

TandEM primary goals are to understand the atmosphere, surface and interior, to determine the chemistry, and to derive constraints on the origin and evolution of Titan and of the saturnian system as a whole, with an emphasis on Enceladus.

TandEM had been proposed as an L-class candidate mission for the Cosmic Vision 2015-2025 programme in response to the Call for Proposals issued by ESA in March 2007, and has been one of the mission concepts selected by the SSAC in October 2007 for an Assessment study. The SSAC had decided that an Outer Planet mission should be one of the L-class mission candidates for the first slice of the Cosmic Vision plan, and recommended that both TandEM and Laplace (a mission to the Jupiter system) concepts should be studied initially, with a decision on which one to pursue to take place following a better definition of the mission's characteristics.

In early February 2009 ESA and NASA jointly announced that the Europa-Jupiter System Mission, or Laplace (see problem::laplace), would be the candidate for the first L mission.

We transcribe here TandEM interplanetary trajectory transfer problem as an MGA-DSM problem and we allow to instanciate 25 different types, depending on the fly-by sequence adopted. The mission data are taken from those used by a joint ESA/NASA working group that performed, together with industrial partners a preliminary trajectory design for the TandEM mission during the first months of 2008. Please refer to http://www.esa.int/gsp/ACT/inf/op/globopt/TandEM.htm to select the proper instance. A default choice is 6, which corrsponds to an EVEES fly-by sequence. The possibility of adding one additional constraint on the time-of-flight is given. If such a constraint is specified the components x[4]-x[7] are no longer time of flights but they represent the percentage of the remaining time of flight to be used in one leg. Thus the linear constraint on the time of flight is automatically transformed into a box constraint.

The problem is transcribed as an MGA-DSM problem allowing one chemical manouvre per trajectory leg. The objective function is defined as $f = -\log(m_f)$ where $m_f$ is the final spacecraft mass. The problem is also part of the Global Trajectory Optimization database (GTOP)

tandem is a box constrained single objective, continuous optimization problem of dimension 18.

See also: http://www.esa.int/gsp/ACT/inf/op/globopt/TandEM.htm

Author: Dario Izzo (dario.nosp@m..izz.nosp@m.o@esa.nosp@m..int)

Definition at line 80 of file tandem.h.

Constructor & Destructor Documentation

pagmo::problem::tandem::tandem	(	const int	probid = `6`,
		const double	tof_ = `-1`
	)

Constructor.

Instantiates one of the possible TandEM problems

Parameters

[in]	probid	This is an integer number from 1 to 24 encoding the fly-by sequence to be used (default is EVEES). Check http://www.esa.int/gsp/ACT/inf/op/globopt/TandEM.htm for more information
[in]	tof_	(in years) This is a number setting the constraint on the total time of flight (10 from the GTOP database). If -1 (default) an unconstrained problem is instantiated

Definition at line 71 of file tandem.cpp.

Member Function Documentation

std::string pagmo::problem::tandem::get_name ( ) const

virtual

Get problem's name.

Default implementation will return the problem's mangled C++ name.

Returns: name of the problem.

Reimplemented from pagmo::problem::base.

Definition at line 256 of file tandem.cpp.

std::string pagmo::problem::tandem::pretty ( const std::vector< double > & x ) const

Outputs a stream of the trajectory data.

While the chromosome contains all necessary information to describe a trajectory, mission analysits often require a different set of data to understand a trajectory. This method outputs a stream with information on the trajectory that is otherwise 'hidden' in the chromosome

Parameters

[in] x chromosome representing the trajectory in the optimization process

Returns: an std::string with launch dates, DV magnitues and other information on the trajectory

Definition at line 177 of file tandem.cpp.

void pagmo::problem::tandem::set_sparsity	(	int &	lenG,
		std::vector< int > &	iGfun,
		std::vector< int > &	jGvar
	)		const

protectedvirtual

Implementation of the sparsity structure.

This implementation does not make use of problem::base::estimate_sparsity as the numerical difficulties introduced by the objective function definition through a logarithm makes automated detection unreliable (e.g. also SNOPT algorithm fails). Clearly, as the problem is box constrained no sarsity is present.

Reimplemented from pagmo::problem::base.

Definition at line 244 of file tandem.cpp.

The documentation for this class was generated from the following files:

Public Member Functions

Protected Member Functions

Friends

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation